Haptic input systems are used in the industrial and medical sector, but also in the end-user sector, in order to transmit the movement of a user, in particular of at least one hand, to another system. These other systems can be directly actuatable devices, such as e.g. medical instruments, machines, vehicles which can be controlled remotely, robots or the like. Alternatively, the information contained by the input into these haptic input systems can also be implemented in (purely) computer-related applications, such as e.g. in CAD applications or virtual reality.
These haptic input systems usually display different combinations of degrees of freedom and axes, within which a corresponding movement can take place. Here, it is usually possible to find three translational and three rotational degrees of freedom. These degrees of freedom can in each case be provided with or without force feedback. Here, force feedback means either responses from a device to be controlled or responses from a computer system, which experiences the corresponding device in reality or experiences the computer system in virtual reality and, by means thereof, transmits force feedback-type feedback to the user of the haptic input system. In addition to these aforementioned six degrees of freedom of spatial movement, even more functions on the haptic input system can furthermore be provided to the user. A gripper function is such an exemplary function.
This gripper function is an actuation of a device to be controlled (in the real world or in virtual reality), which is achieved by a gripping movement by the respective user using his hand. In this context, a gripping movement is to be understood to mean such a movement in which a user moves at least two of his fingers on one hand toward one another, wherein, in general, at least one of these at least two fingers is a thumb.
In order to detect movements of a finger of a user, U.S. Pat. No. 7,480,600 B2 describes a device in which a thimble is placed onto the fingertip of a user. By means of a suspension device, this thimble is connected to the device described there in such a way that translational movements of the fingertip in space can be detected. Furthermore, the transmission of force feedback to the respective finger has also been described. In order to be able to detect a gripping movement of a user, U.S. Pat. No. 7,480,600 B2 proposes combining a plurality of the above-described devices and therefore track e.g. three fingers of one hand in terms of their motion by means of an appropriate combination device. This means that every finger to be tracked of the corresponding hand of the user is provided with an appropriate thimble, which is then in each case connected to respectively one of the devices described therein by means of its own suspension device.
Apart from the comparatively complicated procedure of having to provide each finger individually with a thimble, the design of the combination device described in U.S. Pat. No. 7,480,600 B2 leads to a complicated system of rods being present. This system becomes ever more complicated with increasing numbers of fingers to be identified, and so structural problems may also already occur in the case of three or more fingers.
U.S. Pat. No. 7,411,576 B2 describes a haptic interface, which, in particular, is suitable for movement and hence control in accordance with the aforementioned six degrees of freedom. This haptic interface has a user interface element, which consists of a nose and a detachable user connection portion. This detachable user connection portion can have various designs and can therefore have different gripper shapes. In particular, a stylus-like shape is described. In the described shapes, provision is furthermore made for function keys on the stylus-like design, which function keys can serve for controlling the haptic input system. These function keys are configured as conventional pushbuttons, which, when required, can be pressed by a finger of the user.
Controlling a gripping movement is not provided for by U.S. Pat. No. 7,411,576 B2. The otherwise-described function keys merely serve to modify the operation of the haptic input system and are moreover arranged in such a way that ergonomic operation of the haptic input system in the aforementioned U.S. Pat. No. 7,411,576 B2, as could be desired e.g. when operating cutting tools by means of such a haptic input system, is not possible.
US 2005/0043719 A1 also describes a haptic input system with a gripper part with separate input pushbuttons. Like in U.S. Pat. No. 7,411,576 B2, these input pushbuttons can be allocated various functions.
US 2008/0154246 A1 likewise describes a system for carrying out robot-controlled surgical interventions. To this end, provision is made on a handle, which, like in U.S. Pat. No. 7,411,576 B2, substantially has a stylus-like design, for a corresponding user to press together two gripping elements arranged pivotably to one another in order to cause a correspondingly similar moving together of the gripping or cutting elements in the object to be controlled. To this end, these gripping elements are securely arranged on the handle. Furthermore, US 2008/0154246 A1 provides for a corresponding user, who actuates the gripping elements for actuating the gripping or cutting tools, which are to be controlled, to have an approximate feeling for how strongly a corresponding gripping tool or cutting tool is actuated. In US 2008/0154246 A1, this is implemented by virtue of elastic, in particular also springy, elements being provided which, for example, also have different elasticity in different portions. As a result of this, a transition from e.g. a wide opening region to a narrower opening region of a corresponding tool should be effected to the user.
Like in U.S. Pat. No. 7,411,576 B2, there is also relatively non-ergonomic gripping of the handle in this case. The gripping elements arranged on this handle are, as a result of the provision with these respectively mechanical components, furthermore disadvantageous to the extent that these elastic/mechanical components are subjected to a certain amount of wear and tear, making replacement necessary from time to time. However, as a result of the secure integration into the handle in this device, this is connected with much effort. In addition to the comparatively bad ergonomic design and the aforementioned aspects in relation to wear and tear, comparatively complicated cleaning/sterilizing is furthermore required due to the depicted embodiment of the handle if the device is to be used in the vicinity of an operation site. An application of a general sheath would not redress this in this case either, since this once again reduces the user comfort of such a device.
US 2008/0167662 A1 describes a control system for controlling a robot, in particular for surgical interventions. In this respect, the device provides various control devices, for example joysticks, in order to actuate the corresponding instrument to be controlled. In order to transmit a corresponding haptic feedback from the instrument to be controlled to the user, US 2008/0167662 A1 proposes that a corresponding user makes use of a tactile glove. This glove is configured in such a way that it contains appropriate inflatable elements, which are to transfer the respective forces to a hand of a respective user, which forces the user would also experience if he were to actuate the corresponding instrument directly. In other words, the device of US 2008/0167662 A1 offers a conventional control system with the corresponding control devices, the disadvantages of which were already mentioned above, and in this case integrates a feedback system in the form of a glove.
Even if the proposed glove offers optimization in respect of the feedback functions of such a system, the conventional input equipment furthermore remains in respect of the ergonomics and safe operability of a corresponding control system. The aforementioned disadvantages of unsafe operation, possible slippage and difficult control due to inexpedient ergonomic conditions are not removed by the use of such a tactile glove either.
Although, purely theoretically, the haptic input systems described above in an exemplary manner enable the transmission of gripper information to a target system, this is however brought about by means of e.g. a freely suspended hold of the hand and, individually for each finger, by a complicated connection of the hand to the individual haptic input systems in U.S. Pat. No. 7,480,600 B2 or by means of a more stylus-shaped arrangement in U.S. Pat. No. 7,411,576 B2 and US 2008/0154246 A1, which arrangement is likewise unsuitable for targeted controlled gripper-like movement. As a result of the comparatively non-ergonomic actuation, there can easily be slippage or shifting from the actual position in both devices, which may be fatal, particularly in difficult applications such as e.g. a surgical intervention or complicated mechanical interventions. This also applies to the system from US 2008/0167662 A1, which substantially resorts to conventional input equipment for control purposes. Moreover, the above-described devices establish the connection to the user by means of elements securely arranged on the devices, like e.g. in U.S. Pat. No. 7,480,600 B2, US 2008/0154246 A1 and US 2008/0167662 A1, or by means of elements with an at least comparatively complicated design, which are not suitable for in-depth cleaning either, like in U.S. Pat. No. 7,411,576 B2. As a result, these devices are disadvantageous for uses in the medical sector, particularly in surgical interventions in the vicinity of the operation site.